This invention relates to the use of a highly acidic metalated organic acid as a food additive.
Acids and alcohols have been widely used as ingredients to decontaminate and preserve food and other biological materials. The addition of an organic acid to foodstuffs is called acidulation. Acidulated foods are defined in the Code of Federal Regulations (21 CFR) as any consumable food product with a pH of less than 4.6 and produced to comply with current Good Manufacturing Practices (xe2x80x9ccGMPxe2x80x9d) for food and food additives. These products have cost and taste advantages over heat-treated foods. Acidulated foods give a better taste of xe2x80x9cfreshnessxe2x80x9d than those that have been heat treated.
Newer methods of food preservation include the addition of non-pathogenic bacteria to prevent spoilage and irradiation with ionizing radiation causing preservation. Each of these methods has cost, quality and food safety issues associated with implementation. Acidulation of food with mineral and/or organic acids remains the least costly and most effective method of food preservation.
In the late 80""s and early 90""s, researchers in Japan developed strong ionized water (xe2x80x9cSIWxe2x80x9d) as disinfectants. The SIW was established as water with a pH of 2.7 or less, having an oxidation-reduction potential of 1,000 mv or more, and chlorine concentration of 0.8 ppm or more. The SIW is prepared by electrolysis of water.
Electrolysis of tap water has also been used to produce xe2x80x9cstrong acid waterxe2x80x9d and xe2x80x9cstrong alkali waterxe2x80x9d both of which were claimed to have antiseptic properties.
U.S. Pat. No. 5,830,838 to Wurzburger, et al. describes a solution for cleaning metal surfaces. The solution is prepared by mixing calcium hydroxide and potassium hydroxide with equivalent sulfuric acid in water then passing the solution through a 10 micron filter. The resulting concentrate can be diluted depending on the degree of surface oxidation of the metal to be treated.
U.S. Pat. No. 5,895,782 to Overton, et al. describes a solution for cleaning metal surfaces particularly non-ferrous alloys such as copper, brass and high strength aluminum alloys. The solution is prepared by mixing Ca(OH)2 and KOH with equivalent sulfuric acid in water then passing the solution through a 10 micron filter. The resulting concentrate can be used full strength or diluted depending on the degree of surface oxidation of the metal to be treated.
International Publication WO 94/09798 describes a pharmaceutical composition for treatment of disease, injury and other disorders. The pharmaceutical composition comprises a complex of a calcium-containing component and a sulfate-containing component in a pharmaceutically acceptable carrier. The reference teaches the isolation from natural materials, such as peat, the inorganic compositions. The inorganic preparations comprise an alkaline, aqueous or organic, or mixture thereof, extract of peat. Peat is extracted with aqueous solutions, organic solutions or water-miscible organic solvents at temperature from below room temperature up to the boiling point of the solvents. The preferred extracting solvents are those having a pH of at least 9. Biologically active constituents of fractionated peat preparations were identified as CaSO4.2H2O (gypsum), CaSO4.K2SO4.H2O (syngenite, also referred to as the double salt of gypsum) and K3Na(SO4)2 (apthitalite) by X-ray powder diffraction analysis. The reference also describes the synthesis of syngenite.
It is thus desirable to be able to have a source of xe2x80x9cacidity,xe2x80x9d or H3O+, without the unwanted disadvantages and be able to reduce environmental and safety hazards associated with acid hydrolysis. Preferably, this source of xe2x80x9cacidityxe2x80x9d should be able to prevent re-contamination following decontamination, not induce bacterial resistance, not alter the taste, color or smell of treated foodstuffs, not create any odor, effective in water in a wide range of temperatures, relatively free of danger when overdosed, can be neutralized after use, not carcinogenic or mutagenic, non-toxic, almost harmless to the environment, and can be stored for a long period of time without decomposition or turning into hazardous compound.
The control of microbial growth is necessary in many practical situations, and significant advances in agriculture, medicine and food science have been made through study of this area of microbiology. xe2x80x9cControl of growthxe2x80x9d means to prevent growth of microorganisms. This control is effected in one of two basic ways: (1) By killing microorganisms; or (2) by inhibiting the growth of microorganisms. Control of growth usually involves the use of physical or chemical agents which either kill or prevent the growth of microorganisms. Agents which kill cells are called xe2x80x9ccidalxe2x80x9d agents; agents which inhibit the growth of cells, but without killing them, are referred to as xe2x80x9cstaticxe2x80x9d agents. Thus the term xe2x80x9cbactericidalxe2x80x9d refers to killing bacteria and xe2x80x9cbacteriostaticxe2x80x9d refers to inhibiting the growth of bacterial cells. A xe2x80x9cbactericidexe2x80x9d kills bacteria, a xe2x80x9cfungicidexe2x80x9d kills fungi. xe2x80x9cSterilizationxe2x80x9d is the complete destruction or elimination of all viable organisms in or on an object being sterilized. The object is either sterile or not, there are no degrees of sterilization. Sterilization procedures involve the use of heat, radiation or chemicals, or physical removal of microorganisms.
Microorganisms tend to colonize and replicate on different surfaces resulting in adherent heterogenous microbial accumulations termed xe2x80x9cbiofilms.xe2x80x9d Biofilms may form on surfaces of food substances, processing equipment and instrumentations. The microorganisms in the biofilms may include bacteria, fungi, viruses, and protozoans. Since food safety is a national priority, any product that can help by solving a multitude of problems associated with food production is desirable. Removal and control of biofilms which harbor dangerous microbial contamination is a sanitation goal that needs to be achieved. It is also desirable to be able to safely decontaminate water and nutriment by lowering pH to levels where contaminants would react and organisms cannot live.
Current sanitizing, disinfectant and pesticide products on the market for these uses contain residues of chlorine, ammonia, organic iodine, metal salts and other deleterious residues. It is desirable to have a way that would preclude these residues by promoting killing and/or acid hydrolysis without the presence of deleterious chemicals. Additionally, this method should generate few hazardous volatile gases. Importantly, it is highly desirable to have a composition that can control the growth of, and kill, microorganisms and, at the same time, destroy the products, generated by, or associated with, the microorganisms.
The present invention involves the use of a highly acidic metalated organic acid as a food additive. The acidic composition having an acidic pH value and an acid normality value and the composition is prepared by mixing a monovalent or polyvalent cation and an organic acid in the presence of a strong oxyacid, wherein the resultant acidic composition is less corrosive to a ferrous metal than a solution of a mineral acid having the same acidic pH value as that of the acidic composition, and wherein the acid composition is more biocidal than a mixture of the organic acid and a metal salt of the organic acid which mixture has the same acid normality value as that of the acidic composition. The acidic composition can be prepared by mixing at least one regenerating acid, at least one metal base, and at least one organic acid, wherein the amount of the regenerating acid is in excess of the equivalent amount of the metal base. One aspect of the present invention pertains to method of preparing the highly acidic metalated organic acid.
One aspect of the present invention pertains to a composition of a highly acidic metalated organic acid (xe2x80x9cHAMOxe2x80x9d). The composition may have a suspension of very fine particles, and it has a monovalent or a polyvalent cation, an organic acid, and an anion of a regenerating acid, such as the anion of a strong oxyacid. The term xe2x80x9chighly acidicxe2x80x9d means the pH is in the acidic region, below at least about 4, preferably 2.5. HAMO of the present invention is less corrosive to a ferrous metal than a solution of a mineral acid having the same acidic pH value as that of the acidic composition. HAMO is also more biocidal than a mixture of the organic acid and a metal salt of the organic acid which mixture having the same acid normality value as that of the acidic composition.
Broadly, one way HAMO can be prepared is by mixing the following ingredients: (1) at least one regenerating acid; (2) at least one metal base; and (3) at least one organic acid, wherein the equivalent amount of the regenerating acid is in excess of the equivalent amount of the metal base. The equivalent amount of the metal base should be about equal to that of the organic acid. Instead of using a metal base and an organic acid, a metal salt of the organic acid can be used in place of the metal base and the organic acid. The insoluble solid is removed by any conventional method, such as sedimentation, filtration, or centrifugation.
Generally, HAMO can be prepared by blending or mixing the necessary ingredients in at least the following manners:
1. Regenerating acid+(metal base+organic acid);
2. Regenerating acid+(metal base+salt of organic acid);
3. (Regenerating acid+salt of organic acid)+base; and
4. Regenerating acid+salt of organic acid.
The parenthesis in the above scheme denotes xe2x80x9cpre-mixingxe2x80x9d the two ingredients recited in the parenthesis. Normally, the regenerating acid is added last to generate the HAMO. Although each of the reagents is listed as a single reagent, optionally, more than one single reagent, such as more than one regenerating acid or organic acid, can be used in the current invention. The number of equivalents of the regenerating acid must be larger than the number of equivalents of the metal base, or those of the metal salt of the organic acid. When the organic acid is an amino acid, which, by definition contains at least one amino group, then the number of equivalents of the regenerating acid must be larger than the total number of equivalents of the metal base, or metal salt of the organic acid, and the xe2x80x9cbasexe2x80x9d amino group of the amino acid. Thus, the resultant highly acidic metalated organic acid is different from, and not, a buffer.
As used herein, a regenerating acid is an acid that will xe2x80x9cre-generatexe2x80x9d the organic acid from its salt. Examples of a regenerating acid include a strong binary acid, a strong oxyacid, and others. A binary acid is an acid in which protons are directly bound to a central atom, that is (central atom)-H. Examples of a binary acid include HF, HCl, HBr, HI, H2S and HN3. An oxyacid is an acid in which the acidic protons are bound to oxygen, which in turn is bound to a central atom, that is (central atom)xe2x80x94Oxe2x80x94H. Examples of oxyacid include acids having Cl, Br, Cr, As, Ge, Te, P, B, As, I, S, Se, Sn, Te, N, Mo, W, or Mn as the central atom. Some examples include E2SO4, HNO3, H2SeO4, HClO4, H3PO4, and HMnO4. Some of the acids (e.g. HMnO4)cannot actually be isolated as such, but occur only in the form of their dilute solutions, anions, and salts. A xe2x80x9cstrong oxyacidxe2x80x9d is an oxyacid which at a concentration of 1 molar in water gives a concentration of H30+greater than about 0.8 molar.
The regenerating acid can also be an acidic solution of sparingly-soluble Group IIA complexes (xe2x80x9cAGIISxe2x80x9d). AGIIS can be prepared by mixing or blending materials given in one of the following scheme with good reproducibility:
(1) H2SO4 and Ca(OH)2;
(2) H2SO4, Ca(OH)2, and CaCO3;
(3) H2SO4, Ca(OH)2, CaCO3, and CO2 (gas);
(4) H2SO4 and CaCO3;
(5) H2SO4, CaCO3, and Ca(OH)2;
(6) H2SO4, CaCO3, and CO2 (gas);
(7) H2SO4 and CaSO4;
(8) H2SO4, Ca(OH)2, and CaSO4;
(9) H2SO4, CaSO4, and CaCO3;
(10) H2SO4, CaSO4, CaCO3, and Ca(OH)2;
(11) H2SO4, CaSO4, CaCO3, and CO2 (gas); and
(12) H2SO4, CaSO4, CaCO3, CO2 (gas), and Ca(OH)2.
Thus, preferably, AGIIS is prepared by mixing calcium hydroxide with concentrated sulfuric acid, with or without an optional Group IIA salt of a dibasic acid (such as calcium sulfate) added to the sulfuric acid. The optional calcium sulfate can be added to the concentrated sulfuric acid prior to the introduction of calcium hydroxide into the blending mixture. The addition of calcium sulfate to the concentrated sulfuric acid appears to reduce the amount of calcium hydroxide needed for the preparation of AGIIS. Other optional reagents include calcium carbonate and gaseous carbon dioxide being bubbled into the mixture. Regardless of the use of any optional reagents, it was found that the use of calcium hydroxide is desirable.
One preferred method of preparing AGIIS can be described briefly as: Concentrated sulfuric acid is added to chilled water (8xc2x0-12xc2x0 C.)in the mixing vessel, then, with stirring, calcium sulfate is added to the acid in chilled water to give a mixture. Temperature control is paramount to this process. To this stirred mixture is then added a slurry of calcium hydroxide in water. The solid formed from the mixture is then removed. This method involves the use of sulfuric acid, calcium sulfate, and calcium hydroxide, and it has several unexpected advantages. Firstly, this mixing is not violent and is not exceedingly exothermic. Besides being easy to control and easy to reproduce, this mixing uses ingredients each of which has been reviewed by the U.S. Food and Drug Administration (xe2x80x9cU.S. FDAxe2x80x9d) and determined to be xe2x80x9cgenerally recognized as safexe2x80x9d (xe2x80x9cGRASxe2x80x9d). As such, each of these ingredients can be added directly to food, subject, of course, to certain limitations. Under proper concentration, each of these ingredients can be used as processing aids, acidulants and in food contact applications. Their use is limited only by product suitability and current Good Manufacturing Practices (xe2x80x9cGMPxe2x80x9d).
The sulfuric acid used in the preparation of AGIIS or for this invention is usually 95-98% FCC Grade (about 35-37 N). Concentration of sulfuric acid used to generate AGIIS can range from about 0.05 M to about 18 M (about 0.1 N to about 36 N), preferably from about 1 M to about 5 M. It is application specific. The term xe2x80x9cMxe2x80x9d used denotes molar or moles per liter.
In the preparation of AGIIS, normally, a slurry of finely ground calcium hydroxide suspended in water (about 50% of W/V) is the preferred way of introducing the calcium hydroxide, in increments, into a stirred solution of sulfuric acid, with or without the presence of calcium sulfate. Ordinarily, the mixing is carried out below 40xc2x0 C., preferably below room temperature, and more preferably below 10xc2x0 C. The time to add calcium hydroxide can range from about 1 hour to about 4 hours. The agitation speed can vary from about 600 to about 700 rpm, or higher. After mixing, the mixture is filtered through a 5 micron filter. The filtrate is then allowed to sit overnight and the fine sediment is removed by decantation.
The calcium hydroxide used for AGIIS or for this invention is usually FCC Grade of about 98% purity. For every mole of concentrated acid, such as sulfuric acid, the amount, in moles, of calcium hydroxide used is application specific and ranges from about 0.1 to about 1.
The calcium carbonate is normally FCC Grade having a purity of about 98%. When used with calcium hydroxide as described above for the preparation of AGIIS, for every mole of a concentrated acid, such as sulfuric acid, the amount, in moles, of calcium carbonate ranges from about 0.001 to about 0.2, depending on the amount of calcium hydroxide used.
The optional carbon dioxide in the preparation of AGIIS is usually bubbled into the slurry containing calcium hydroxide at a speed of from about 1 to about 3 pounds pressure. The carbon dioxide is bubbled into the slurry for a period of from about 1 to about 3 hours. The slurry is then added to the mixing vessel containing the concentrated sulfuric acid.
Another optional ingredient in the preparation of AGIIS is calcium sulfate, a Group IIA salt of a dibasic acid. Normally, dihydrated calcium sulfate is used. As used in this application, the phrase xe2x80x9ccalcium sulfate,xe2x80x9d or the formula xe2x80x9cCaSO4,xe2x80x9d means either anhydrous or hydrated calcium sulfate. The purity of calcium sulfate (dihydrate) used is usually 95-98% FCC Grade. The amount of calcium sulfate, in moles per liter of concentrated sulfuric acid ranges from about 0.005 to about 0.15, preferably from about 0.007 to about 0.07, and more preferably from about 0.007 to about 0.04. It is application specific.
An organic acid is an acidic compound containing carbon. It includes carboxylic acid, amino acid, acidic vitamin, sulfonic acid, phosphonic acid, and others. A carboxylic acid is an organic compound containing an xe2x80x94COOH group, i.e., a carbonyl attached to a hydroxyl group. A carboxylic acid can be a mono-carboxylic acid, a di-carboxylic acid, or a tri-carboxylic acid. A mono-carboxylic acid can be represented by a general formula of R1xe2x80x94COOH, wherein R1 can be: H; C1-C4 saturated alkyl; C2-C5 unsaturated alkyl with 2 or less double bonds; or C2-C5 unsaturated alkyl with 2 or less triple bonds; CH3CH(OH); HOCH2(CHOH)4; or R2CH(NH2), wherein R2 is H, C1-C4 saturated alkyl, C6H5CH2, p-HOxe2x80x94C6H4CH2, H2N(CH2)4, HOCH2, or CH3CHOH. A di-carboxylic acid can be represented by a general formula of HOOCxe2x80x94R3xe2x80x94COOH, wherein R3 can be: (CH2)m, in which m can be 1-3; (CHxe2x95x90CH); CH2CH(OH); H(OH)Cxe2x80x94CH(OH); or (CH2)pCH(NH2), in which p is 2 or 3. A tri-carboxylic acid can be represented by a general formula of HC)OCR (COOH)COOH, wherein R4 can be: CH2C(OH)CH2; or CH2CHCH2. Although some amino acids have been included in the general category of mono-carboxylic acid, it is known in the art that amino acids include: alanine; arginine; aspartic acid (asparagine); cysteine (cystine); glutamic acid (glutamine); glycine; histidine; hydroxylysine; hydroxyproline; isoleucine; leucine; lycine; mehtionine; phenylalanine; proline; serine; threonine; tryptophan; tyrosine; valine; aminoadipic acid; diaminobutyric; ornithine; pipecolic acid; sarcosine; and thiiodothyronine (thyroxine).
The metal base can be in the form of an OHxe2x88x92, CO3=, HCO3xe2x88x92, or O= salt. The metal can be a monovalent metal, a polyvalent metal, all transition and rare earth elements, Sn, Pb, or Bi. Examples of monovalent: metals include elements in Group IA. The polyvalent metals can be a divalent metal or a trivalent metal. Examples of divalent metals include elements in Group IIA, except Be; and examples of trivalent metals include elements in Group IIIA, except B. Preferably the metal is Mn, Mg, Ca, Fe(II), Cu(II), Zn(II), Ce, Ni, Pd, Cr, Ti, Zr, Co, Al, Sn, Pb, Bi, V(III), Cd, Hg, Pt, Hf, and other first-row lanthanides, except Pm. More preferably, the metal is Mg, Ca, Fe(II), Cu(II), Zn, Cr, or Co.
Salts of an organic acid as used in this application include the salts of the metals, discussed above, salts of the organic acids, also discussed above, and others.
The term xe2x80x9cbiocidalxe2x80x9d means destruction of a biological contaminant. A xe2x80x9cbiological contaminantxe2x80x9d is defined as a biological organism, or the product of biological organism, such as toxin, or both, all of which contaminate the environment and useful products. This biological contaminant results in making the environment or product hazardous.
Biological contaminants, such as bacteria, fungi, mold, mildew, spores, and viruses have potentially reactive substances in their cell wall/membranes; however, they hide in cells (viruses and some bacteria)and/or secrete biofilms (most bacteria, fungi, mold and mildew) to protect them from the environment.
Bacteria form or elaborate intracellular or extracellular toxins. Toxin is a noxious or poisonous substances that: (1) are an integral part of the bacteria; (2) are an extracellular product (exotoxin) of the bacteria; or (3) represent a combination or the two situations, formed or elaborated during the metabolism and growth of bacteria. Toxins are, in general, relatively complex antigenic molecules and the chemical compositions are usually not known. The harmful effects of bacteria come not only from the bacteria themselves, but also from the toxins produced by bacteria. Toxins produced by bacteria are just as, if not more, hazardous to the product than the bacteria themselves. Ordinary disinfectants, such as quaternary ammonium compounds, will kill bacteria but may have no effect on bacterial toxins and endotoxins. In fact, many disinfectants actually contribute to the endotoxins problems by causing their release from the killed bacteria. The bacterial toxins and endotoxins can cause serious adverse effects in human and animals. Endotoxins are a major cause of contamination in food products, in the production of pharmaceuticals, medical devices, and other medical products.
The outer covering, i.e. epidermis, of animals and cuticle of plants resist the growth and/or entry of the above microorganisms into the interior of the complex organism. One of the microbial growth prevention methods used by plants and animals is the maintenance of a surface pH or secretion of a coating that is not conducive to the attachment and propagation of micro-organisms. After a plant product is harvested or an animal product processed, these products loose the ability to resist the infestation of micro-organisms.
The composition of the present invention was found to be a xe2x80x9cpreservative.xe2x80x9d The composition is minimally corrosive; however, it can create an environment where destructive micro-organisms cannot live and propagate, thus prolonging the shelf-life of the product. As is known in the art, formic acid is not as corrosive to a ferrous metal as is a mineral acid, such as hydrochloric acid. Yet, formic acid solution is more corrosive to a galvanized roofing nail than is a solution of HAMO. In one experiment, after 48 hours of air-drying, a galvanized roofing nail, which had been dipped for 20 minutes at room temperature in a solution of formic acid with a pH of 1.5, showed obvious, visible corrosion. Yet, under similar conditions, no such obvious, visible corrosion was observed for a galvanized roofing nail having been dipped in a solution of HAMO (prepared from lactic acid, calcium hydroxide and regenerated with phosphoric acid) at a pH of 1.44.
The utility of the method of preservation demonstrated herein is that additional chemicals do not have to be added to the food or other substance to be preserved because the inherent low pH of the mixture is preservative. Since preservative chemicals do not have to be added to the food substance, taste is improved and residues are avoided. Organoleptic testing of a number of freshly preserved and previously preserved food stuffs have revealed the addition of composition improves taste and eliminates preservative flavors. The term xe2x80x9corganolepticxe2x80x9d means making an impression based upon senses of an organ or the whole organism.
The composition of the present invention was found to be biocidal. The composition was found to be biocidal to E. coli, and other bacteria.
As used herein, the term xe2x80x9cnutrimentxe2x80x9d means something that nourishes, heals, or promotes growth and repair the natural wastage of organic life. Thus, food for a human or an animal are all examples of nutriment. Sometimes, food for an animal is termed xe2x80x9cfeed.xe2x80x9d Other examples of nutriment include beverages, food additive, beverage additive, food supplement, beverage supplement, seasoning, spices, flavoring agent, stuffing, sauce, food. dressing, diary products, pharmaceutical, biological product, and others. The nutriment can be of plant origin, animal origin, or synthetic.
The following examples are provided to further illustrate this invention and the manner in which it may be carried out. It will be understood, however, that the specific details given in the examples have been chosen for purposes of illustration only and not be construed as limiting the invention. Unless otherwise defined, the amount of each ingredient or component. of the present invention is based on the weight percent of the final composition.